Manufacture of electrical conductors.



. g oss REl-tKtNUt.

sTATEsPATENT OFFICE.;

' moms n. ALLEN AND momma: B. CoULTEIB, or NIAGARA rams, YORK,

ASSIGNOBS TO THE CABBOBUNDUM COMPANY, OF N IAGABA FALLS, NEW YORK. A CORPORATION OF PENNSYLVANIA;

IANUFAC'I'URE (3F ELECTRICAL CONDUC'JZ'OR S.

Specification oi Letters Patent. Patented Oct. 20, 1914. 1 Application med November "21, 1911. Serial in. 601,584.

. E To all whom it may concem: ofmanufacture which w e refer Q eZmec- Be it known that we, THOMAS B. ALLEN tion with impregnating t e silicon carbid and LEONARD B. COULTER, residents of Niagarticles with graphite; We take .a rod. con- 55 ara Fails, in the county of Niagara and, sisting of 70 per cent. h weight of silicon State of New York, have invented a new and carbid and '30 per cent. y. weight of I 6. 1; useful Improvement in the Manufacture ofamic Binder, consisting preferably of flghi: 15

Electrical Conductors, of which the followl molip. This rod is then immersed maize full,'clear,- and exact description. '111 a colloidaLsolution pf ggaphitg in water 60.

invention is designed to improve the containing 10 per cent. by we ht of gra'ph 10- manufacture of electrical CODdUCtOI'SyPflP- ite. Itis advisable-to subject t e vessel conticularly those of the ceramic type, formed, taining the rod and. the a nude. to a for example, by a mixture. ofsilicon carb id, vacuum or pressure or both. alter gtply, as

1,114,665. 80 Drawn-13.

crystalline alumina, or similar materials combined v or other binder and" aphite or other" conductin material.

uch mixtures have. been'forfiie "inYJ'sHi'fi and then heated to; vitrify the" ceramic binder; but conductors of this class have been found to have very uneven or unequalelectrical conductivities. It has also been found very -diflicult to produce an article having a high conductivlty, since the high percentage of graphite or other conductive material seriously afiects the mechanical strength of the article. Conductors formed of aphite and cla have also been tried, but are ound unsa isfactory since they shatter and are otherwise destroyed when subjected toa high voltage electrical discharge.

We have found that we can overcome these difliculties and produce electrical conductors having gluite uniform conductivities which do not atter under the discharge of high voltage current, by impregnatingv a ai-sm'table porous article .with a very finely divided form of mat i'ial such as g1 -a pl 1 i t e gree of impregnation takes place, After standing in the solution for a certain length rod is removed and heated to a temperature of from 350 to 400 0., in order to coinpletely dehydrateitl Tfie rod is then ound on its surfaces to remove the surface eposit of graphite and is then in a finished condilong, one inch diameter, treated in the man'- ner described will be.found to have an electrical resistance of substantially one hundred ohms. 1

The electrical resistance of the product will vary according to the porosity of the article, since the degree of impre ation is proportional to the porosity of t e article. This porosit may be. vari coarseness o the silicon-carbi the porosit increasing with thecoarseness of the carbi Theporosity is also increased b increasing the' roportion of silicon carbi to that of the inder., We have further found' that under theseconditions amuch greater de- 65 of time, preferably twoto three hours, the

tion. As a concrete example, a rod 8 inches b altering the For carrying out our process we can use the electrical conductivity of the article may I a large number of porous articles; and may be increased still further. by epgating the use difierent forms of finely divided conducim re ation with graphite asecond or even 40 two material, such, for example, as the colaT't 1r pr more times. In this way an 155- loidal solution oggraphite in ater, zso'rii ticle in a obtained having a very low 1 incnfl'fknown'as' agq'uada-g, or the colloidal electric resistance. We have. also found splut on gfgraphi n an; commonly known it is advantageous to coat the article with as odd or the colloidal solution of a haze of any well known composition in 45 metals w ch are ectr1c con uc ors. order to prevent oxidation thereof by the This grade of graphite is also known as air when raised to high temperatures. deflocculatediigraph te, and is described in A preferable method of lazin the arthe Umted States patents of E. C. Acheson, ticles is as follows: The t orou El dried Nos. 843,426 and 844,989. We may also use article is coated with a lazew 'c has a. 50 other co 0 1ve..,mater1a1 guspgnded ir comripsition as fo1lowsfi0- arts b 2 water or other ML e. weig t, Na 0 18.6 parts'b'y weig t, M%) e I now escnbe one specific method '62 p y weight,-K,O 28.2 parts y The advantages of our invention will be obvious to those skilled in the art since the difiiculties with synthetic conductors of this character are obviated and a practical commercial method provided by which a conductor of high efficiency may be obtained. The articles so made have a very uniform electrical conductivity and do not shatter under the discharge of high voltage current. They are found to retain their conductivity even under continual discharge and while heated to red heats. They are therefore highly useful in, for examp eythe lightning arrester industry, on account of high carryin capacity. y

any variations may be made in the materials employed for the article and for impregnating it, without departing from our invention. .The method ofimpregnating may be varied and the conducting material ma be suspended in air or gases instead of in 'quids.

The novel article produced by the foregoing method forms the subject matter of a divisional application.

We claim:

1. In the manufacture of electrical conductors, the steps consisting of impregnating a porous article with a colloidal solution of graphite and heating said article.

2. In the manufacture of electrical conductors, the step consisting of im regnating a silicon carbid article with a co oidal solution of an electrical conductor. f

3. In the manufacture of electrical conductors, the step consistinglof im regnating a silicon carbid article wit a co oidal solution of graphite. v

In testimony whereof, we havehereunto set our hands.

. T-HOS. B. ALLEN;

- L. B. COULTEB. Witnesses:

F. W. HILLMANN- C. H. Gnmmwoon. 

